In ETV6::RUNX1+ BCP-ALL case ALL4, which was stratified as a standard-risk case, but later developed a relapse, a somatic loss of 12 Mb length encompassing the TP53 gene locus was detected (chr17:5,423,849–18,312,173 bp) (Suppl. Here, TP53 is linked to acute lymphoblastic leukemia.